Note: At first things were a little bit weird. Both of the repos had changes initally that were not in the other. Fortunately in my example the differences didn't really matter and I just went with one of them. I did this by branching the no.de version into a node branch and then checking it out ontop of master after merging in the ghithub branch. Once I did this everything was fine. Pulling, if you need to do it, is a little different as well, because you might be pulling from two different places:

git pull github master

Overall, for a small project that's being hosted both by github and Joyent, this solution seems to work pretty darn well. Let me know how if it works for you or alternatively, why it's a bad idea!